A variety of cephalosporin derivative compounds with various substitutions on a beta-lactam core have antibacterial activity. Cephalosporin compounds with a quaternary ammonium group at the 3-position of the cephalosporin beta lactam core structure and an aminothiazole/oxime structure at the 7-position can provide antibacterial activity against multiple types of bacteria, including Gram-negative bacteria Pseudomonas aeruginosa (Pa). For example, ceftazidime and cefpirome, which include the cephalosporin core with an aminothiazolyl group at the 7-position and a quaternary salt substituent at the 3-position, have antibacterial activity against a wide spectrum of bacteria from Gram-positive bacteria in addition to Pseudomonas aeruginosa. However, even compounds such as ceftazidime and cefpirome may not be satisfactory in the antibacterial activity against both Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA). In addition, infectious diseases caused by methicillin-resistant Staphylococcus aureus (MRSA) continue to present significant clinical challenges. There remains a need for novel cephalosporin antibiotics which have improved antibacterial activity also against these and other bacteria.